Plans to repave Commercial Boulevard near Costco and lay down gravel at some subdivisions and a trailhead on Glacier Highway halted last week because contractors were afraid of exposing their workers to the potent carcinogen.

Exposure to asbestos can cause lung diseases such as asbestosis and mesothelioma.

Several contractors say they will not touch the rock from Stabler's Point again until new test results come back in a few weeks.

The city and Secon Construction collaborated on tests at the quarry and Juneau's rock-crushing operations last Thursday to learn how much asbestos is embedded in the rock.

In addition, the Alaska Department of Transportation and Public Facilities, which uses Stabler's Point rock for some road projects, has shipped off mineral samples for analysis at the Colorado School of Mines.

So far, city engineers do not believe there is a public health risk from the tremolite-bearing rock and they have not found asbestos at other quarries in town.

Still, some Juneau residents say they're uneasy about the rock.

Michelle Helmick-Murphy acquired about 190 tons of Stabler's Point rock to fill in her residential lot. She was planning to cover it with dirt and plant a vegetable and flower garden.

She's now wondering if that's a good idea. "I'm going to wait for the test results before getting excited about it," she said Friday.

Asbestos seems to be part of the local geology, said Rorie Watt, the city's chief capital-improvement project engineer.

Watt said he found a piece of rock appearing to contain asbestos at Sandy Beach near the old Treadwell Mine last week.

Tremolite is a mineral that can contain one of the most dangerous forms of asbestos, but asbestos fibers are only dangerous when they are inhaled.

It can take 15 to 40 years for asbestos-related diseases to show up in people's lungs, said John Wheeler, a toxicologist with the federal Agency for Toxic Substances and Disease Registry in Atlanta.

"What you really want to evaluate is air levels," Wheeler said.

City officials say they believe there is little risk to the public from Stabler's Point rock because contractors bury it under dirt or mix it with asphalt.

Watt said he doesn't plan to track all of the locations where Stabler's Point rock has been taken in town unless upcoming test results show a potential health hazard.

In California, scientific modeling has shown a significant public health risk from asbestos-related diseases because toxic dust from exposed rock along roads and construction projects invaded homes, schools and ball fields.

State and federal officials have spent millions paving over asbestos-tainted gravel roads and covering up asbestos-contaminated soil in a high school soccer field in El Dorado County, Calif.

The state of Alaska and the city of Juneau do not have asbestos ordinances, Watt said. He intends to draft local rules for handling asbestos that are based on California's regulations.

People who blast rock at the quarry or crush it would likely face the greater risk of asbestos exposure, scientists said.

The quarry contains thin veins of the fibrous material, and workers have been blasting rock there for at least five years.

City and state transportation officials said they didn't realize it was there until a private contractor commissioned tests earlier this summer and shared the results with other contractors and the city on July 21.

The city sent out a memo Friday telling quarry users and contractors that federal law requires them to wear respirators when they are working around asbestos.

"Please be assured that we are concerned as you are about the situation at Stabler's Quarry, and we are working on (starting) a testing and monitoring program that will enable us to make informed decisions regarding the quarry's continued operation," wrote Watt, the city's chief capital-improvement project engineer, in the Friday memo.

Secon has contracted with SCS Engineers, a national environmental consulting firm, to test the quarry rock.

A Secon geologist from California grabbed 12 samples from rock-crushing operations and the quarry Thursday.

The Mine Safety and Health Administration collected air tests at the quarry Tuesday but many in Juneau doubt the results will be useful because the tests were taken in the rain.

The city plans to use hundreds of thousands of square yards of Stabler's Point rock as fill for the new Dimond Park high school in the near future.

The ongoing testing could confound the school district's construction schedule. "Basically, we're waiting to see what happens. When I get the call from (the city), that's when my concern goes up," said Juneau School District Maintenance and Projects Director Deb Morris.

The district will not tolerate any safety hazard to its students, she said.

Secon planned to use the rock for an ongoing ramp expansion project at Juneau International Airport. Bingham said Secon changed plans and is now using rock from the city's Hidden Valley quarry instead.

Secon will not use, process or sell any products made from Stabler's Point rock until the quarry gets a clean bill of health, he said.